Consider where you want to do the majority of your activities.
Are you moving here just to dive, or would you like to be able to enjoy other outdoor activities?
If you want to do other stuff, Northern Florida is more doable in the summer than Southern Florida.
Do you want to be able to shore dive or just boat dive? That will define you're east vs west coast.
Honestly if you are willing to drive 3 hours, live elsewhere and just fly down. It's a ~3 hour flight from Baltimore DC would be less. Fly into pbi on a Friday night, for boat diving or fly into Jax or somewhere up north for cave diving.
Fly with a carryon only, rent tanks down here.
I'm not trying to talk you out of anything.
Just think what you really think you're going to do.
Florida is miserably hot ~8 months of the year. And filled with snowbirds and tourists ~6 months out of the year.
Living where you vacation sounds fun.